Henricia sp. (Pl. 3, a, b).

Material Examined:

One specimen, Sta. 1818.

Size:

R/r = 30/6 mm.

Description:

Disc flat, arms long, slender, tapering evenly to blunt tips; shallow sulci present interradially.

page 22

Abactinal skeleton close reticulum of oblong, trilobate or cruciform plates obscured by thick membrane; plates with from 5–15 short flattened, hyaline spinelets which terminate in a number of uneven points. Near arm tips paxillae smaller, seldom more than 5 or 6 spines.

Papulae conspicuous, one to 3 in interspaces between paxillae, present on disc and to arm tips, absent from narrow interradial sulcal areas.

Madreporite interradial in position, midway between centre and edge of disc; inconspicuous, more or less circular, dissected by number of deep grooves, ridges crowned by rows of short, thorny headed spines.

Marginal plates inconspicuous. Superomarginals rectangular or proximally slightly curved forming fairly regular row along underside of arms, each with about 23 short spinelets similar to those of abactinal surface.

Inferomarginals small, corresponding to superomarginals, spinelets fewer. Conspicuous papulae present between marginal plates.

Adambulacral plates very regular with one or 2 blunt-tipped, compressed spines deep in furrow and row of 2 or 3 finely thorny spikes actinally, more or less level with furrow edge. Subambulacral spines 15–20, thorny, crowded, irregularly arranged in 2 or 3 rows.

Oral plates with crowded rather thorny-headed spinelets; furrow spines 6–8, suboral spines similar, 9 or 10, arranged in 2 almost regular rows.

Ambulacral grooves, deep, narrow, tube feet in 2 rows with small sucking discs.

Remarks:

There is much disagreement over the taxonomic status of New Zealand species of Henricia. The present specimen cannot be confused with H. ralphae Fell for the body form and armature of the abactinal, marginal and adambulacral plates is different. It agrees, however, with H. lukinsii (Farquhar) in the spinulation of the abactinal and marginal plates but it differs in the body form and also in the armature of the adambulacral and oral plates. In many ways it resembles H. compacta (Sladen) from a similar locality, but it can be disinguished by the different body form and the more numerous subambulacral spines. The presence of 2 spines deep in the furrow is apparently a variable character as it occurs in some specimens of H. compacta. There also seems considerable variation in the body form and arm length of specimens of H. compacta but in none recorded so far are the arms as thin and slender as in the present specimen. Differences in the adambulacral armature, the fewer abactinal papulae and the body form separate the present specimen from H. compacta aucklandiae.

Geographical Distribution:

Present material from west of Cape Farewell, South Island, New Zealand.

Depth Range:

908–915 m.

Locality:

"Eltanin" Sta. 1818, 40° 15′–40° 17′ S., 168° 16′–168° 18′ E.; 908–915 m.

Location of Specimen

United States National Museum.